bfl-api

name bfl-api description BFL FLUX API integration guide covering endpoints, async polling patterns, rate limiting, error handling, webhooks, and regional endpoints with Python and TypeScript code examples. metadata {"author":"Black Forest Labs","version":"1.0.0","tags":"flux, bfl, api, integration, webhooks, rate-limiting"} BFL API Integration Guide Use this skill when integrating BFL FLUX APIs into applications for image generation, editing, and processing. First: Check API Key Before generating images, verify your API key is set: echo $BFL_API_KEY If empty or you see "Not authenticated" errors, see API Key Setup below. Important: Image URLs Expire in 10 Minutes Result URLs from the API are temporary. Download images immediately after generation completes - do not store or cache the URLs themselves. When to Use Setting up BFL API client Implementing async polling patterns Handling rate limits and errors Configuring webhooks for production Selecting regional endpoints Building production-ready integrations Quick Reference Base Endpoints Region Endpoint Use Case Global https://api.bfl.ai Default, automatic failover EU https://api.eu.bfl.ai GDPR compliance US https://api.us.bfl.ai US data residency Model Endpoints & Pricing Credit pricing: 1 credit = $0.01 USD. FLUX.2 uses megapixel-based pricing (cost scales with resolution). FLUX.2 Models Model Path 1st MP +MP 1MP T2I 1MP I2I Best For FLUX.2 [klein] 4B /v1/flux-2-klein-4b 1.4c 0.1c $0.014 $0.015 Real-time, high volume FLUX.2 [klein] 9B /v1/flux-2-klein-9b 1.5c 0.2c $0.015 $0.017 Balanced quality/speed FLUX.2 [pro] /v1/flux-2-pro 3c 1.5c $0.03 $0.045 Production, fast turnaround FLUX.2 [max] /v1/flux-2-max 7c 3c $0.07 $0.10 Maximum quality FLUX.2 [flex] /v1/flux-2-flex 5c 5c $0.05 $0.10 Typography, adjustable controls FLUX.2 [dev] - - - Free Free Local development (non-commercial) Pricing formula: (firstMP + (outputMP-1) * mpPrice) + (inputMP * mpPrice) in cents FLUX.1 Models Model Path Price/Image Best For FLUX.1 Kontext [pro] /v1/flux-kontext $0.04 Image editing with context FLUX.1 Kontext [max] /v1/flux-kontext-max $0.08 Max quality editing FLUX1.1 [pro] /v1/flux-pro-1.1 $0.04 Standard T2I, fast & reliable FLUX1.1 [pro] Ultra /v1/flux-pro-1.1-ultra $0.06 Ultra high-resolution FLUX1.1 [pro] Raw /v1/flux-pro-1.1-raw $0.06 Candid photography feel FLUX.1 Fill [pro] /v1/flux-pro-1.0-fill $0.05 Inpainting Tip: All FLUX.2 models support image editing via the input_image parameter - no separate editing endpoint needed. Use bfl.ai/pricing calculator for exact costs at different resolutions. Image Input for Editing Preferred: Use URLs directly - simpler and more convenient than base64. Single image editing: curl -X POST "https://api.bfl.ai/v1/flux-2-pro" \ -H "x-key: $BFL_API_KEY " \ -H "Content-Type: application/json" \ -d '{ "prompt": "Change the background to a sunset", "input_image": "https://example.com/photo.jpg" }' Multi-reference editing: curl -X POST "https://api.bfl.ai/v1/flux-2-pro" \ -H "x-key: $BFL_API_KEY " \ -H "Content-Type: application/json" \ -d '{ "prompt": "The person from image 1 in the environment from image 2", "input_image": "https://example.com/person.jpg", "input_image_2": "https://example.com/background.jpg" }' The API fetches URLs automatically. Both URL and base64 work, but URLs are recommended when available. Multi-Reference I2I FLUX.2 models support multiple input images for combining elements, style transfer, and character consistency: Model Max References FLUX.2 [klein] 4 images FLUX.2 [pro/max/flex] 8 images Parameters: input_image , input_image_2 , input_image_3 , ... input_image_8 Prompt pattern: Reference images by number in your prompt: "The subject from image 1 in the environment from image 2" "Apply the style of image 2 to the scene in image 1" "The person from image 1 wearing the outfit from image 2, in the pose from image 3" For detailed multi-reference patterns (character consistency, style transfer, pose guidance), see flux-image-best-practices/rules/multi-reference-editing.md Rate Limits Tier Concurrent Requests Standard (most endpoints) 24 Polling vs Webhooks Approach Use When Polling Scripts, CLI tools, local development, single requests, simple integrations Webhooks Production apps, high volume, server-to-server, when you need immediate notification Start with polling - it's simpler and works everywhere. Switch to webhooks when you need to scale or want event-driven architecture. Key Behaviors Polling : Response includes polling_url for async results URL Expiration : Result URLs expire after 10 minutes Webhook Support : Configure webhook_url for production workloads API Key Setup Required : The BFL_API_KEY environment variable must be set before using the API. Quick Check echo $BFL_API_KEY If Not Set Get a key : Go to https://dashboard.bfl.ai/get-started → Click "Create Key" → Select organization Save to .env (recommended for persistence): echo 'BFL_API_KEY=bfl_your_key_here' >> . env echo '.env' >> .gitignore # Don't commit secrets See references/api-key-setup.md for detailed setup instructions. Authentication x-key: YOUR_API_KEY Basic Request Flow 1. POST request to model endpoint └─> Response: { "polling_url": "..." } 2. GET polling_url (repeat until complete) └─> Response: { "status": "Pending" | "Ready" | "Error", ... } 3. When Ready, download result URL └─> URL expires in 10 minutes - download immediately Related Prompting best practices (T2I, I2I, typography, colors): see the flux-image-best-practices skill Multi-reference patterns (character consistency, style transfer, pose guidance): see flux-image-best-practices/rules/multi-reference-editing.md References references/api-key-setup.md - API key creation and configuration references/endpoints.md - Complete endpoint documentation references/polling-patterns.md - Async polling implementation references/rate-limiting.md - Rate limit handling strategies references/error-handling.md - Error codes and recovery references/webhook-integration.md - Webhook setup and security Code Examples Note: cURL examples are preferred by default as they work universally without requiring Python or Node.js. Use language-specific clients when building production applications. references/code-examples/curl-examples.sh - cURL examples (recommended) references/code-examples/python-client.py - Python client references/code-examples/typescript-client.ts - TypeScript client Quick Start Example 1. Submit Generation Request curl -s -X POST "https://api.bfl.ai/v1/flux-2-pro" \ -H "x-key: $BFL_API_KEY " \ -H "Content-Type: application/json" \ -d '{"prompt": "A serene mountain landscape at sunset", "width": 1024, "height": 1024}' Response: { "id" : "abc123" , "polling_url" : "https://api.bfl.ai/v1/get_result?id=abc123" } 2. Poll for Result curl -s "POLLING_URL" -H "x-key: $BFL_API_KEY " Response when ready: { "status" : "Ready" , "result" : { "sample" : "https://..." , "seed" : 1234 } } 3. Download Image curl -s -o output.png "IMAGE_URL" Tip: Result URLs expire in 10 minutes. Download immediately after status becomes Ready . 4. Multi-Reference Example Combine elements from multiple images: curl -s -X POST "https://api.bfl.ai/v1/flux-2-pro" \ -H "x-key: $BFL_API_KEY " \ -H "Content-Type: application/json" \ -d '{ "prompt": "The cat from image 1 sitting in the cozy room from image 2", "input_image": "https://example.com/cat.jpg",